From disney i really enjoy Maleficent , I just love how sarcastic she is .
Then from marvel I really like Loki and Venom .
And finally from Dc I luv Harley Quinn
I like the Disney's Evil Queen just because I love ABC's Once upon a time series (up to season 6 only, season 7 is a mess),
Marvel's Erik Killmonger from Black panther, because Michael B. Jordan played this character and he's hawt., DC's The ventriloquist from Batman, toys that talks are creepy.
Well, in Disney I would go with Ursula, I love her!!
About Marvel I guess Loki gave us one hell of a villain (some people are tired of him, but in the first Avengers he was marvelous, pun intended).
In DC I'll go with Heath Ledger's Joker (in Batman The Dark Knight)